Perforating explosive projectile



Se t. 13, 1955 E BRANDT 2,717,552

PERFORATING EXPLOSIVE PROJECTILE Filed Feb. 26, 1946 -4 Sheets-Sheet l Sept. 13, 1955 E. w. BRANDT 2,717,552

PERFORATING EXPLOSIVE PROJECTILE Filed Feb. 26 1946 4 Sheets-Sheet 2 Fig-3 Sept. 13, 1955 E. w. BRANDT 2,717,552

PERFORATING EXFLOSIVE PROJECTILE Filed Feb. 26, 1946 4 Sheets-Sheet 5 Sept. 13, 1955 E. w. BRANDT 2,717,552

PERFORATING EXPLOSIVE PROJECTILE Filed Feb. 26, 1946 4 Sheets-Sheet 4 United States Patent 0 PERFORATIN G EXPLOSIVE PROJECTILE Edgar William Brandt, Geneva, Switzerland, assiguor to Anstalt fiir die Entwicklung von Erfindungen und iGewer-blichen Anwendungen Energa, Vaduz, Liechenstein Application February 26, 1946, Serial No. 650,334 In Switzerland February 10, 1944 Section 1, Public Law 690, August 8, 1946 Patent expires February 10, 1964 3 Claims. (Cl. 10256) The present invention concerns a perforating explosive projectile intended to furnish, at the moment of impact, a powerful perforating effect by formation and ejection at very great speed of a perforating core, this projectile including: a shell whose front part is deformable at the impact, a load of explosive placed in the rear part of this shell, the said load having in its front face, fairly distant. from the shells head, a cavity which increases in diameter from rear to front, a sheet metal hood applied against this cavitys wall, means for preventing the displacement of the hood during transportations and handling, a sensitive percussion and firing device mounted on the projectiles head, a detonator placed in the explosive load behind the hood, means for transmitting fire from the percussion device to the detonator, the hood being capable of folding back upon itself under the explosive deflagration effect at the impact, in order to transform itself into a compact perforating core thrown forward at very great speed by the powerful action of the explosive gaseous expansion.

Experience shows that such a projectile is extraordinarily efiicient against armour, the perforating core thrown upon it having in fact a considerable speed (over 2000 metres per second) and this, independently from the shooting range and from the actual speed of the projectile, since it is the explosive load of the projectile itself which, at impact, throws the core against the target at point blank range.

The light weight of the new projectile makes it possible, moreover to fire it from light and handy weapons,

capable of being carried and used by a single man.

The whole shell may be made of a material having a density less than that of the hood.

However, within the limits imposed by constructional and resisting necessities for the practical use of the projectiles covered by the present patent, the component parts, and in particular the outside wall, will be of the least possible thickness and weight, with the exception of the explosive load and the inside hood, the importance and weight of which will be, on the contrary, brought to their maximum as far as is necessary.

These arrangements make it possible to substitute for a certain weight of inert materials a corresponding weight of explosive and a considerable elfective power on which, for a certain total weight of the projectile, directly depends the useful perforating eifect. By replacing the greatest part of the metallic shell dead weight by explosive, one secures this result that the explosive, in addition to the inertia effect which it gives, in a way similar to that of the metallic shell, supplies a considerable supplement of energy which comes itself to incfease the propulsive effect exerted on the hood and, in consequence, the speed and the perforating power of said hood transformed into a core.

This substitution of material and this addition of an explosive power to the inertia effect permit utilizing a great saving in weight and thus to produce a much lighter 7 2,717,552 Patented Sept. 13, 1955 projectile, still capable, however, to furnish the same perforating effect, or else, with the same weight, to realize a projectile having a far greater perforating power.

On this account, a great number of light existing weapons can be brought into massive action for fighting against tanks.

The explosive load will advantageously include two superposed masses of cast explosive and powdered explosive, the detonator being placed between the two masses and, preferably, set in the powdered explosive part located beneath the other.

One thus realizes a good priming and a good deflagra tion of the cast or less sensitive explosive within its whole mass, which ensures an even closing of the hood.

The contact of the two masses of explosive is preferably ensured over the whole of the bottom surface of the cast explosive.

In order to promote a regular collapse of the hood, it will be advantageous to cause the cast explosive to cling snugly to the hood.

To this end, one can provide the hood with a rough outside surface and the explosive will be cast on this surface so as to form a load which will then be introduced into the projectile.

By reason of the adherence between the explosive load and the hood, the retention of the latter in order to prevent its displacement during transportations, handling, etc. is ensured by the explosive load, which it is only necessary to secure in place inside its shell. This retention can be obtained by simple pasting with an appropriate material, as well as by means of a cap covering the annular base of this explosive load. This can, at the same time, constitute an air-tight element avoiding any contact of the charge with the outside atmosphere and the air contained inside the cavity provided in front of the perforating cone.

Other advantages and features of the invention will be shown by the following description.

On the attached drawing, given solely by way of example:

Fig. 1 is a diametrical section of a projectile in accordance with the invention.

Fig. 2 is a corresponding section on a plane through the axis of a projectile of alternative design.

Fig. 3 is a partial axial section of a projectile showing details of a structure according to this invention.

Fig. 4 is a view partly in elevation and partly in axial section of the projectile showing an alternative design of the form of execution of Fig. 3.

According to the drawings, the projectile in accordance with the invention includes a shell, the conical head 1 of which is capable of smashing itself against the target. The middle part 2 of the shell connects with the bottom 3 which is ogival. In case of need there can be provided on the head 1 some ribs as shown in 60 in Fig. 21, intended to strengthen the resistance to shocks during the transportations and handlings.

In the lower parts 2, 3 of the shell is placed the explosive load formed by two superposed masses 4 and 5. The upper mass 4 consists of high explosive of strong effect, but of relatively less sensitiveness than the lower mass 5, and for example, may be cast; and the lower mass 5 preferably consists of powdered and compressed explosive which is more easily detonated and acts as a relay to defiagrate the upper, less sensitive mass 4.

On its front face, the mass 4 presents a deep conical cavity tapering from front to rear. Against the wall. of this cavity is applied a metallic hood or cone 6, immobilized in position by a collar 7 fastened on the shell, at the bottom of the conical head 1 of the latter. This collar is preferably made with a thickness markedly greater than that of the walls 1, 2 of the shell. It presents, towards the rear, against the external circular end of'the explosive load "4, apart or facet 7a slanting as regards the hood axis. Thefacet 7a is followed by another .one 7b fairly perpendicular to the hood axis, and then-by a'second slanting facet 70 or lip which protrudes over the base of the hood. The facet 70 has a diameter increasing from rear to front.

'The point or apex of the cone 6 is'turned towards the bottomand its 'base is markedly distant'from the side wall of the :shell, so that the cone is surrounded by a great thickness of explosive over all its height, even at theplane of its base. The cone 6 is preferably made of steel.

' The walls of the projectile are, not only in the ogive 1, but also in the parts 2 and 3 of the shell, as thin and as light as possible withiregard to the strains which they have to'with'stand as well during the transportations or handlin'gs'as at the time of'shooting. These walls can advantageously'be .made'of a substance (or of substances) of'a lower densi'tythan that of the cone 6 which must be made of steel. It will thus be possible to make the ogive'l, as well as the fuse holder 10 in a substance having a magnes'ium'base, and the rest of the shell of an aluminium alloy. The sum of the weights of the explosive charge and of the hood is at least equivalent to the weight of the other component parts of the projectile: shell, fuse, etc.

The functioning is as follows:

'At the shooting time, internal explosive load 4, 5 remains immobilized inside the shell 2, 3 by the cone 6,

the whole being so arranged as to prevent any undesirable deformation of the explosive under the influence of the propulsive pressure and of the rebounding.

Over the trajectory, the cone, held into its place by its stop 7, also opposes 'itself'to any displacement towards the front or the load by effect of inertia, while the projectile is slowed down by the resistance of the air.

At themoment of' impact, the sensitive fuse 9 is instantaneously brought into action by contact with the target. The fire is transmitted to the detonator 12, which, in its turn, causes the high explosive 4 to detonate by the medium of the powdered load 5 acting as a relay.

The defiagration travels from the rear to the front with the maximum possible quickness and power thanks to the extent'of the surface" of contact of therelay charge 5 with the compressed explosive4. Owing to the judicious spreading of the explosive towards the cone base, the generated gases'act' powerfully over the total surface of the cone 6 which, under the influence of the considerable pressure produced, is violently pushed forwards and at the same time closed upon itself.

By this instantaneous effect on a very short travel (practically less than half of its height), the steel cone 6 having thin walls is transformed and forged into-a compact core, of a much smaller diameter, and is thrown at'extreme speed on the target (an armour plate for in stance) which it pierces with great facility.

The thin head 1 smashes itself on the target at the very-moment when the core forms itself and, because of itslight mass, opposes practically no resistance at all to the passage of the core.

'The perforating effect is obtained by the collection of an explosive power acting primarily over a great surface of comparatively-thin metal to which it imparts a considerable speed and by the restitution of the whole of this power, concentrated on a much smaller surface (practically about twenty times smaller) to act on the armour.

The collar 7 covering the end of the explosive load forms a protective screen against the prematurepropagation of the gases in directions other than those which facilitate the collapsing and the ejection of the hood 6 towards the front. To this effect of the collar7 there adds itself that of the front head 1 of the projectile (Figure 1-),.-(generally of a conical orogival shape),

which also tends to prevent, or at any rate to retard and "reduce any*antagonistic action of the gases on' the core.

It goes without saying that to the dynamic effect of the core there is added the erosive effect of the gases from the explosive which are thrown forward at very high speed.

Theprojectile of the Figure 1 -is intended to be 'fired in a weapon having a smooth barrel utilising feeble ,pressures, such as a mortar for instance. The shell'1, 2,"3 is fusiformand is fitted-at the rear witha stabilizing tail119. The throwing can be effected by the arms and means currently used for projectiles fired from mortars in actual service.

The general operation at the time of impact has been described above. The fire transmission between the head fuse 9 and the detonator .12 is effectedby a strong primer 29a fitted at the head of the projectile and capable:

(i) Without transmitting tube or liaison part, to operate thedetonator 12 at a distance;

(ii) Of destroying the head fuse 9, to throw laterally and to cause the disappearance of any resisting part likely to produce any decrease in the effect of the perforating core, which is thus free to act directly against the armour to be pierced.

The Figure 2 shows a projectile similar to that of the Figure l, but intended to be utilized as a grenade or aircraft bomb.

The annular collar 7 (shield or screen) which will be advantageously made of a light and comparatively plastic substance: cork, cardboard,etc. has for object to avoid the loss of gases-towards the front of the hood. This loss, without the screen, would not only reduce the action of the charge of explosive-on the hood, but would also have the result that the gases thus escaping forwards would form on thetarget an antagonistic gaseous cushion likely to crease the inertia effect and the resistance of the screen preventing the gases from going towards the front.

On the other hand, this ogival head 1 and the collar 7 will preferably fit on to the middle part 2 containing the explosive load with .a streamline curve so that the projectile may have the best possible ballistic qualities.

Finally, the thickness or mass of the collar 7, whether this is made of one or .of several parts, of one or of severalsubstances'will' be decreased towards the interior and the exterior of the hood (Figure 3). These provisions contribute to secure a good functioning as a whole of the parts involved-to get the highest possible efficiency of the explosive action and, in consequence, the ejection at very high speed of the perforating core.

The substance constituting the hood (cone) will have to present an elongation coefiicient as high as possible in order to permit the collapsing and closing effect to take place regularly and in an even and regular manner, this condition being necessary to secure the best possible result.

Apart from that, the shell wall containing the explosive charge must also present itself elongation properties as high as possible, in order to be capable, before complete dislocation under the action of the explosive thrust, to constitute an extensible screen, the self-inertia of which retarding as much as possible and over the greatest possible course the explosive expansion.

Good results will be obtained by constituting the charge 4 of a mixture, in equal parts, of pentrite and of tolite, and the relay-charge 5 of a compressed explosive cake (-tetryl or similar).

The detonator' 12 will be preferably of the mixed type, primed with lead nitride, in order to secure a very quick and powerful priming.

Closeadherence of the cone 6-t0 the wall of the charge 4 will be necessary. It will be possible to secure this, for

instance, by giving to the cone 6 a rough outside surface by sand blasting and in casting the explosive over this surface. The load thus constituted, the cover of which will be formed by the cone 6, will then be introduced in the projectile and applied on the relay charge 5.

It is advantageous to give to the two explosive charges 4 and 5 a great surface of contact, in order to secure a uniform and simultaneous detonation of the high explosive 4 within all its mass, which facilitates the regular formation of the core. This surface of contact, instead of being plane, might be curved or step-wise.

The assembling of the various parts of the projectile must be efiected in conditions permitting to secure a good tightness, this condition being all important to secure the operation as previously described. The components, that is to say the explosives as well as the metallic parts must, at assembling time, be in a state of absolute dryness.

Similarly, the cavity provided in the front face of the explosive could, instead of being conical, take a curved or step-wise shape, the hood 6 being of course of a corresponding shape so as to always exactly fit the wall of the cavity. However, the conical shape is preferable.

The projectile in accordance with the invention may be executed indiiferently as a shell for rifled or smooth barrels, as a rifle or pistol grenade, as an aircraft bomb or grenade, etc. the invention being applicable, generally speaking, every time that the desire is for a perforating effect on armour, even of the greatest thickness.

The Figure 3 shows details of design of a rifle grenade, the inside arrangement of which is similar to that of the projectile of Figure 2, but still difiers on the following points:

The percussion fuse 9 is placed behind and at certain distance from the front end of the deformable head 1 of the shell of the grenade. This fuse is fitted on an inside head or wall 41 distant from the shell 1 and resting against the shield 7. The inside head 41 is centered, at its base 42, by the outside head 1. The fitting of the fuse 9 can be effected by any suitable means: simple forcing, staking, crimping, pasting with a varnish, etc.

The firing from the fuse 9 to the detonator 12 takes place, :as in the case of the Figure 1, without transmitting tube or special connecting part. The primer 20a of the fuse 9 acts upon detonation to emit the flame which is transmitted directly along a path for initiating the action of the detonator 12; and serves at the same time for destroying the head 1 of the shell and the inside fuse holder head 41. The front end of the projectile includes a structure extending rearwardly into the hollow space, such structure may be the outer wall of the primer 20a. At the apex of the cone 6 is fitted a safety device of the detonator, intended to prevent any untimely fire transmission to the explosive load. This device includes, in the example shown, a socket 43 resting on the front head of the detonator 12 and centered in the end of the cone 6. In this socket are housed mobile obturation parts such as balls 44, held in place by a retaining part constituted, for instance, by a ring or sleeve 45 of an inside diameter greater than that of the balls 44 and provided with lugs 46 bent towards the inside. The ring 45 may slide from front to rear in the socket 43, but is prevented from so doing before the moment of shooting by the lugs 46 facing the balls. The ring 45 is kept inside the socket 43 by the bent end 4311 of the latter. When the balls 44 occupy the position shown by a continuous line, they shut the access to the detonator 12 and any fire transmission from the primer 20a to the detonator is impossible.

When the round is shot, the ring 45 remains behind by inertia and the lugs 46 are sheared by the balls 44. Then, while the grenade is subjected to a negative acceleration that is, a deceleration, due to air resistance, the balls 44 having a tendency to maintain their initial speed move forward and out of the socket 43, thus liberating the passage for fire transmission. The balls 44 finally reach the front of the shell in the neighbourhood of the fuse 9, illustrated by the dotted line position in Fig. 1, normally radially outside the fuse structure and thus outside the direct axial path of fire transmission to the main detonator 12, being maintained during the deceleration and upon detonation in such position by the projection of the fuse structure into the hollow front end, illustrated by the dotted lines in Fig. 3.

The detonator safety device being at the same time an armament retarding device permits the use of a head fuse reduced to its simplest expression and not compulsorily provided with an armament retardation.

The body or socket of the detonator safety device occupies the aperture at the apex of the cone or hood 6 and, at the time of shooting the projectile, prevents any disintegration of the explosive load towards the apex of the cone 6 and, at the time of detonation, prevents the gases from penetrating inside this cone, which would only decrease the useful effect.

The propulsion tube 20 of the grenade bears a tail 47 having the general shape of a cone expanding from front to rear and ending by a less inclined crown 47a. In the cone are cut some sort of windows 48 obtained by pushing inside the out part, of which the blades 49, more or less obliquely directed in comparison with the cone surface 47, serve to increase the stabilizing effect by their braking action on air streams. These blades may possibly be inclined so as to form a screw with a view to impart to the grenade a slight gyration favouring accurate shooting.

In order to further decrease the thickness of the walls of the outside wall of the projectile in accordance with the invention, to bring down its weight to a minimum and to increase at the same time its resistance to shocks and the practical ruggedness for manipulation and transports, one may provide a ribbing, a grooving or a corrugation of the shells head, of the rear part of this shell and also of the tail.

These ribs or grooves may be so arranged as to in crease at the same time the ease of assembling, to determine accurately the position of parts between themselves and to constitute a locking system.

By way of example, the Figure 4 shows a grenade having a conical head 1 provided with longitudinal ribs 60, the lower base of which stands at 61 on the fuse holder wall 41, also forming solid steps, this arrangement determining exactly the position of the exterior cone 1. The setting is thus achieved with easiness and accuracy.

The same figure shows a tail 47 the arms of which have longitudinal ribs at 62 and having a back crown also fitted with ribs at 63. These arrangements ensure practical stiffness and sturdiness; they permit the use of minimum thicknesses and weights.

It goes without saying that the invention has only been described by way of example and that many changes might be applied to it without departing from its scope.

What I claim is:

1. A projectile having a shell, a head on said shell, a load of explosive located in said shell, said load of explosive being formed with a cavity extending from its front face, said cavity being spaced from the head of the shell and increasing in diameter from rear to front, a sheet metal hood applied against the wall of said cavity, a main detonator located in the explosive load behind the sheet metal hood, said hood having an aperture permitting fire transmission from the cavity to said main detonator, a sensitive head fuse located at the head of the projectile and including a priming detonator and a part positioned for delivering the flame of detonation into and across said cavity, said detonators being held spaced from one another, said part and the cavity providing fire transmission means in a direct path from the priming detonator to the aperture and the main detonator and being elfective solely by the explosion of the priming detonator without any physical connecting part between said priming detonator and .said main detonator; the combination therewith of =-a-rnovable element located in position for obstructing fire transmission through the aperture to the main detonator, a support for-the obstructing element mounted behind the aperture and-cooperative withsaid obstructing element foraxially forward movement thereof through the aperture and into the cavity and therewith out ofobstructing position and a device effective for retainingsaid 'obstructingelement in safety position, said device including a first part cooperative with the obstructing element for preventing such forward movement thereof prior to the firing of the. projectile and yielding uponrearward axial-movement relative to thesupport by inertiaupon .firing of the projectile and thereby vbecoming'effective to free the said obstructing element for its said axial forward movement,anrl -a secondvpart for preventing.forwardtmovement of said first part prior to said firing.

2. A phojectile having a shell, a head'on said shell, a load of explosive located in said shell,-said--load of explosive being formed with a cavity. extending from its front face, said cavity being spaced'from the head of the shell and increasing in diameter from rear to front, asheet metal hood applied against the walliof said cavity, -a socket having a longitudinal'passage .coaxial with the hood aperture, a main detonator behind the socket, said hood having at its rear an aperturepermitting fire transmission from the cavity to said socket passage-a sensitive head fuse located at the headof the projectileand including a priming detonator and a part positioned for delivering the flame 'of detonation into and across said cavity, said detonators being held spaced from one another, said part and the cavity providing fire-transmission means in a direct path from thepriming detonator to the aperture and passage and thus to the main detonator and being effective solely by the explosion. of thepriming detonator'without any physical connecting part between said priming detonator and said .main detonator and said main detonator; and comprising in combination therewith an element in. the socketpassage for obstructing the same and movable axially forwardly through the aperture and into said cavity and therewith out of such obstructing position, a first part supported by the socket and cooperative with said obstructing element for preventing forward movement of the obstructing element prior to firing, and yielding under-inertia effects upon firing of the projectile whereby said' obstructing element and socket-supported part are cooperative-by inertia effects during the positive forward acceleration at firing for freeing said obstructing elementso that it can move forwardly in the socket and out of said aperture into said cavity, whereby said elementand part provide a safety means for preventing fire transmission along said path prior to the propulsion of saidshell on tits-trajectory, and a second part carried by the socket for preventing axial forward movement of said firstpart prior to firing.

3. A projectile having a shell, 9. head on said shell, a load of explosive located in said shell, said load :of explosive being formed with a cavity extending from its front face, said cavity being spaced from the head of the shell :and increasing .in diameter from rear to front, a sheet metal hood applied against the wall of said cavity, a socket having a longitudinal passage coaxial with the hood aperture, a main detonator behind the socket, said hood having atits rear an aperture permitting fire transmission from the cavity to said socket passage, a sensitive head fuse located at the head of the projectile and including a priming detonator and a part positioned for delivering the flame of detonation intotand across said cavity, said detonators being held spaced from one another, said part and the cavity providing fire transmission means in adirect path from the priming detonator to the aperture and passage and thus to the main detonator and being effective solely by the explosion of the priming detonator without any physical connecting part between said priming detonator and said main detonator; and comprising in combination therewith an element in the socket passage for obstructing the same and movable axially forwardly through the aperture and out of obstructing position, a sleeve slidable in the passage and having deformable means effective to prevent forward movement of theobstructing element and having means effective to prevent rearward movement of the sleeve during handling prior to firing, and means on the socket for preventing forward sliding of the sleeve in said socket, whereby said element and part provide a safety means for preventing fire transmission along said path prior to the propulsion of said shell on its trajectory, said sleeve means being effective during the positive acceleration at firing to free said obstructing element for movement forwardly in the sleeveand socket and into the space,

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